The present invention relates to an electric power tool which is rotary driven by a motor.
A so-called electronic clutch-type electric power tool has been known as disclosed in Japanese Unexamined Patent Application Publication No. 2006-281404 and Japanese Unexamined Patent Application Publication No. 2010-214564. An electric power tool of this type is configured such that driving of the motor is stopped when a rotational torque of an output shaft on which a tool element, such as a driver bit, is mounted exceeds a predetermined upper limit value (hereinafter, also referred to as a “set torque”).
The electric power tool of this type is configured such that the motor can be driven both in a forward direction and a reverse direction in order to allow tightening and removal of, for example, a screw. By controlling driving of the motor such that the rotational torque of the output shaft does not exceed the set torque regardless of a rotation direction of the motor, a function as an electronic clutch can be achieved.